Find the equation for the line tangent to the parametric curve: $$\begin{array}{r@{\,}c@{\,}l} x & = & t^3 - 4 t \cr y & = & 4 t^2 - t^4 \end{array}$$ at the points where $t = 2$ and $t = - 2$.
For $t = 2$, the tangent line (in form $y=mx+b$) is
$y =$ .
For $t = - 2$ , the tangent line is
$y =$ .